Once more unto the breach, dear friends, once more!

Little more tired than I expected. Oh, well. Hopefully, the coke I'm drinking will keep me coherent and creative for long enough. On with the alternate history!

In our past installment: a small tribe, on the edge of the Sahara desert, discovers a system of plants and water management that allows them to cultivate slightly more arid area than in our timeline. After c. 2000 years of this system being stable, a young priest of the local religion has decided to shake things up, mostly out of greed.

The next ten years were harsh, demanding work for everyone, the priest included. Irrigation ditches had to be dug, cisterns created and filled with the output from the spring. The water-retaining plants had to be carefully cultivated, a few hundred feet of ground made stable and semi-fertile each year. Twice years with low rainfall almost doomed the project, killing even the hardy plants of the desert. Once, an unexpected rainstorm almost flooded out the whole area, threatening to wash away years of work in a single afternoon.
But through each year, the priest learned a little more, and discovered new ways to advance his goal. He learned quickly that the plants had to be expanded slowly, in the proper order. The grasses had to come first, to fix the shifting, loose soil of the desert. Then the shrubs and tubers, to futher fix the soil, and to more throughly distribute the water and nutrients in the soil. Finally, the straight agricultural plants could begin to be planted; hardy, low water grain varieties, and more edible tubers and berry shrubs. It was four years before the first food plants were successfully grown in the new lands. But once they were grown, and successful, the priest knew that he could make his plan work; desert had been transformed.
The drought years taught them that the cisterns needed to be large, and always filled. The second drought year, 8 years into the project, taught them much about proper water rationing - it was no good trying to grow a food crop during a drought; simply maintaining the plants holding the soil was the vital task.
The flash flood taught them all the value of charting watercourses, even dry ones, and the necessity of overplanning their irrigation system. Fields were lost when they drowned because their irrigation ditches overflowed, and precious water simply flowed away into the dust, because little had been done to catch it. New cisterns were built, designed to catch any future overflow, so as not to squander the bounty provided by the rain god.

Finally, after ten long years, the priest (now a middle aged man of 35), had his proof: desert could be, with sufficient work, dedication, and planning, be turned into arrable land. In the process, he had created himself, almost without meaning to, an entire clan of acolytes. Every member of the clan was now at least partially versed in the intricacies of the system, and several were almost as skilled in it as himself. And every member of the clan was fanatically devoted to him; he was viewed almost as a savior, sent by the water god himself. The clan now lived far better than it had before, with the new farmland. In addition, the process of reclaiming the desert had taught them better use of their existing irrigation system, allowing their previous lands to be more productive as well.

The priest now set out on the next stage of his plan. Taking a few trusted followers, leaving the clan in the hands of his most trusted apprentice, he made a journey, beyond the lands of the tribe altogether. He went north, to a leader of one of the more prosperous tribes, and proposed a deal: he could give the leader the secret to conquering his home tribe, and keeping the land fertile this time, as none of the leader's ancestors had been able to do for generations. In addition, he could improve the tribe's own farmland, and even expand it, into the desert border, provided the tribe was willing to work.
The leader was initially sceptical, but the priest convinced him to send agents to the home of his clan. The reports the agents brought back were spectacular: a tiny spring supporting a huge area of farmland, and a clan that knew irrigation and cultivation of marginal areas cold. The leader agreed to the priest's bargain, and began to supply the priest with his long craved-for wealth: a large house, precious goods, good wine, good food, slaves; the whole package.
The next year, the priest's old tribe discovered they were once again being invaded. They sighed, and did what they always did: head for their hilltop fortresses, with permanent water supplies and food for two years or more, and waited for the invaders to find that they could not farm the land. But this time, they were in for a surprise. The invaders did not fail to farm the lands. In fact, in some areas, they actually seemed to be getting better crops than the original tribe had! The people of the area sank into despair: clearly their gods had finally abandoned them, after guarding them for so long. Most fortresses surrendured, and their population merged with the invaders. A few fortresses were taken by siege, or finally were starved out as their food stocks were finally exausted. One or two committed mass suicide rather than be taken. But the tribe was finished, whatever the final end of its people.

But its religion, in a sense, lived on. After his aid had allowed his adopted tribe to conquer his own people, the priest had been showered with riches by a greatful chief. But he still wasn't satisfied. He looked around, and discovered that greater wealth and more luxury were still to be had. And deep in his heart, he felt restless simply lazing about all day. The 10 years of hard labor had left its mark, and he was no longer content with a simple life of lesiure.
So he began to sell his services. He offered, to any that could pay his fee (an enormous amount, by the local standards), to improve existing agriculture, and to add agricultural land to the desert border, provided there was a water source. Some tribes took him up on his offer. He used his clan, still fiercely loyal to him, to guide the adjustment and creation of the agricultural systems. By the end of his life, he had turned 5 oasises into fertile land, and improved the land use of thousands of square miles. He lived in the greatest luxury of practically anyone in 500 miles; he was richer than most tribal chieftans. But all his money was not spent on himself: he created a number of temples to his rain god. They were initially staffed by members of his clan, but as time went on, they began to accept novitiates from the surrounding populace. The temples taught the worship of the rain god, and the agricultural and irrigation methods, so painfully learned. They created a philosophy composed of equal parts profit motive, strong work ethic, and experimental investigation. The ideal priest of the rain god always had his eye on the best way to make a coin, was willing to work harder than anyone else to get it, and was able to think up a new way of doing the job when the old ways failed him.
Within 3 generations of the old priest's death, the religion he, essentially, created had spread far beyond its homeland. The temples were always well paid for their efforts, and all made a point of expanding whenever their coffers and population of priests allowed it. Each temple was independent, but all kept in contact with each other, and were willing to aid each other in times of need. This gave them significant political clout: a tribal chieftan who tried to browbeat, threaten, or overtax a temple on his lands could find himself without a temple, with an irrigation system falling into disrepair without knowledgeable people to maintain it, and his neighbors circling like vultures, waiting for his food supplies to grow low enough to make him an easy conquest.

Over the next 500 years, the water god's religion spread east and west across North Africa. By 650 BC, they had reached Egypt. There, their influence was stymied for a time. Egypt, it seemed, did not need them: the Nile provided all the water and nutrient-rich mud any farmer could want, making the water-god's innovations mostly useless. The best the temples could do was improve the irrigation system slightly. They did have some success in improving the Al Fayum oasis, almost halting its centuries-long decline into a salt flat. However, it was not until c. 500 BC that they made a truly revolutionary change to the Egyptian agricultural experience.

In the south of the nation, an ambitious temple, eager to increase its fortunes and its political power, began a large-scale undertaking. They convinced a provincial governer, himself eager for advancement, to sponser them. The temple began to construct a huge series of cisterns, larger than any before attempted, mostly carved straight into bedrock. They were designed to fill when the river flooded. Then, with the first group of cisterns filled, the water was forced to flow slowly, in shallow, wide channels. In these channels, it deposited its load of nutrient rich silt, which was collected and stored separately. Then the water flowed into large holding cisterns. When the floodwaters receeded, the resivores were full. When the dry season came again, the new resivores provided water to irrigate the land, allowing a longer productive growing season, and the silt collected from the river and hauled away, was able to make formerly marginal land, at the edge of the flood zone, more fertile.

The project succeeded, although it took almost twenty years of work, experimentation, and more than a few dead ends, to finally get all the bugs out. By this time, the governer's son was now the governer, but his father's investment more than repaid itself: the province was able to notably increase its productivity, and thus the taxes it paid to the government (at that time, Egypt was ruled by the Persian Empire). The new system was adopted in many parts of Egypt. Where no good stone for cisterns was found, artifical caves of oven-fired brick were created.

In addition to increasing Egypt's productivity, the success of the rain-god's temple attracted the notice of the Persian emperors. They began to hire temples, enouraging them to move to Asia, where centuries of irrigation had began to take their toll on the land.
The temples began to work in the land of Babylon. This was a differnent task then they had before faced: usually their work involved simply adding water and fixing soil dried and denourished by dryness. Now they had to cope with land actively poisoned, by built up minerals and salts from millenia of irrigation. The work took longer than any project before. They slowly began to learn the tricks and methods to do it, but it required all their ingenuity. They were forced to find plant breeds that could not only flourish in the soil, but purify it. They had to learn how to tell mostly pure water from that which would further salinate the soil, and find some way to select the good water and leave the bad. In fact, before they were even halfway through the work, they had to suffer the disruption of the greatest conquest in history: the wars of Alexander the Great. But Alexander would provide an opportunity greater than any they had ever seen, and change the nature of the rain-god's temple forever.
But that's the next post.